Understanding Gas Fees

Base Fee (Burned)

The base fee is the minimum price per unit of gas required for a transaction to be included in a block. This fee is determined algorithmically by the protocol based on network demand. When blocks are more than 50% full, the base fee increases; when they are less than 50% full, it decreases. Critically, the base fee is burned (permanently removed from circulation), which makes ETH deflationary during periods of high usage. This means every transaction on Ethereum reduces the total supply of ETH.

Priority Fee (Tip)

The priority fee (also called the "tip") is an optional additional payment that goes directly to validators. Including a higher tip incentivizes validators to include your transaction sooner. During periods of high congestion, a higher tip can be the difference between your transaction being confirmed in 12 seconds versus several minutes. Most wallets auto-suggest an appropriate priority fee based on current network conditions.

Max Fee and Gas Limit

When you submit a transaction, you set two parameters: the max fee per gas (the maximum you are willing to pay per unit of gas) and the gas limit (the maximum number of gas units the transaction can consume). The actual cost is calculated as: gas used multiplied by (base fee + priority fee). If the base fee drops below your max fee, you get a refund for the difference. If your gas limit is too low, the transaction fails but you still pay for the gas consumed up to the failure point.

Gas prices on Ethereum fluctuate significantly throughout the day and week. Weekends and early morning hours (UTC) tend to have lower gas prices. Use gas trackers like Etherscan Gas Tracker or GasNow to monitor prices and execute transactions during low-demand periods.

For most DeFi activities, Layer 2 networks offer identical functionality at a fraction of the cost. Bridge your assets to Arbitrum, Optimism, or Base and perform your swaps and trades there. You can save 90-99% on gas compared to Ethereum mainnet.

If you need to perform multiple operations, look for protocols that allow batching. Some DEX aggregators can combine approval and swap into a single transaction. ChainBridge optimizes transaction flow to minimize the number of on-chain operations needed.

Most wallets auto-estimate gas limits with a safety margin. If you understand the transaction, you can sometimes lower the gas limit. However, setting it too low will cause the transaction to fail and you will still lose the gas spent. When in doubt, use the wallet default.

Some protocols like 0x (Gasless API) and UniswapX offer gasless or meta-transaction support where the protocol pays gas on your behalf. ChainBridge integrates with these gasless options, allowing you to swap without paying gas directly in some cases.

Use Permit2-based approvals instead of traditional ERC-20 approvals where possible. Permit2 uses signatures instead of on-chain transactions for approvals, saving you a separate approval transaction. Both 0x and UniswapX on ChainBridge support Permit2.

0x Gasless API

The 0x Gasless API uses meta-transactions where you sign a message (free) instead of sending a transaction (costs gas). A relayer then submits the transaction on your behalf and deducts a small fee from the output tokens. This is especially useful for swaps on Ethereum mainnet where gas costs can be significant.

UniswapX Intent-Based Trading

UniswapX uses an intent-based system where you sign an order describing what you want to trade. Professional fillers then compete to fill your order at the best price, and they pay the gas. The filler profits from the spread between the quoted price and their execution price, while you get gas-free execution and often better prices through Dutch auction mechanics.